Total and split renal function in patients with renovascular hypertension: effects of angiotensin-converting enzyme inhibition.

Thirteen subjects with documented renovascular hypertension receiving chronic (greater than 1 month) therapy with an angiotensin-converting enzyme inhibitor (enalapril or captopril) underwent total and split renal function studies. Total glomerular filtration rate as assessed by inulin clearance was similar to that determined by radionuclide technique. Total effective renal plasma flow as assessed by p-aminohippurate clearance was lower than that determined by radionuclide technique. The glomerular filtration rate and effective renal plasma flow assessed by radionuclide technique of the stenotic kidney was comparatively lower than that of the non-stenotic kidney. No subject demonstrated complete loss of filtration or perfusion of the stenotic kidney. Five of six patients studied prospectively for 2 years have demonstrated stability of total renal function; the sixth patient, having a functional solitary stenotic kidney, has demonstrated stability of function following an initial abrupt decline in glomerular filtration rate and effective renal plasma flow. These results suggest that chronic angiotensin-converting enzyme inhibition therapy is not generally associated with near total absence of filtration of the stenotic kidney as has been suggested previously. Angiotensin-converting enzyme inhibitors may be safely and effectively utilized in the treatment of renovascular hypertension.